Fluorescence amplified fragment length polymorphism compared to pulsed field gel electrophoresis for <it>Listeria monocytogenes</it> subtyping

• Main Authors: Roussel Sophie, Félix Benjamin, Grant Kathie, Dao Trinh Tam, Brisabois Anne, Amar Corinne
• Format: Article
• Language: English
• Published: BMC 2013-01-01
• Series: BMC Microbiology
• Subjects: fAFLP; PFGE; Molecular subtyping; <it>Listeria monocytogenes</it>; Discriminatory power
• Online Access: http://www.biomedcentral.com/1471-2180/13/14

<p>Abstract</p> <p>Background</p> <p>Listeriosis is a severe infection which mainly affects pregnant women, neonates and immuno-compromised adults. ANSES’s Laboratory for Food safety has been the European Union Reference Laboratory (EURL) for <it>L. monocytogenes</it> in the food chain since 2006. Pulsed Field Gel Electrophoresis (PFGE) is routinely used in the EURL for the surveillance of <it>L. monocytogenes</it> isolated from foods, animals and the environment. One of the main EURL activities is to evaluate alternative molecular subtyping methods to PFGE, and integrate their use within the National Reference Laboratories (NRL) network. Since 2008, the United Kingdom (UK)-NRL for <it>L. monocytogenes</it> at the Health Protection Agency (HPA), London, has used fluorescent Amplified Fragment Length Polymorphism (fAFLP) for the routine surveillance of <it>L. monocytogenes</it> isolated from human clinical cases, food and food processing environments in the UK. This study compares fAFLP with PFGE for subtyping <it>L. monocytogenes</it>.</p> <p>Results</p> <p>A panel of 109 <it>L. monocytogenes</it> isolates from either human cases of listeriosis, foods, food processing environments and animals were used for the comparative evaluation. Among these, 2 strains were tested from duplicate culture by both methods. The panel also included field isolates, isolates associated with outbreaks or sporadic cases and reference strains. The two strains tested in duplicate displayed the same fAFLP and PFGE types. Strains known to be epidemiologically associated with one another were found to have unique PFGE and fAFLP types. FAFLP and PFGE divided the strains into 76 and 82 distinct profiles, or types, respectively. The discriminatory index calculated was 0.993 and 0.996 for fAFLP and PFGE, respectively.</p> <p>Conclusions</p> <p>The discriminatory ability of fAFLP was similar to that of PFGE for the subtyping of <it>L. monocytogenes</it> isolates. As a less labour intensive technique fAFLP may be a better method to use than PFGE in investigating outbreaks of human listeriosis and tracking the source of contamination in food processing facilities in real time.</p>